Depends what you mean by "openly gay"
I work in a large hospital with (I presume) a normal complement of gay people. We have a few screaming queens who can be very amusing (they are in effect making a second profession of their gayness), but most of our gay staff don't make a big thing out of it and one only learns of it after quite a while.
I judge people on whether they are kind, able and professional - if they are then they're in by me - their sexual orientation is not my concern and whether it's homo or hetero I see no reason for folk to wave it in my face.
Don't make a secret of it or stand up and loudly announce it - be yourself, do your job well and you'll find that most people (perhaps disappointingly) don't care that much.
Make a great performance out of being gay or straight and you'll just irritate people.